I am a physician and behavioral scientist at Duke University. My research and writing explores the quirks in human nature that influence our lives — the mixture of rational and irrational forces that affect our health, our happiness and the way our society functions. (What fun would it be to tackle just the easy problems?) I am currently exploring controversial issues about the role of values and preferences in health care decision making, from decisions at the bedside to policy decisions. I use the tools of decision psychology and behavioral economics to explore topics like informed consent, shared decision making and health care spending. My books include Pricing Life (MIT Press 2000) and Free Market Madness (Harvard Business Press, 2009). My newest book, Critical Decisions (HarperCollins), explores the challenges of shared decision making between doctors and patients.

When Americans Rejected Small Pox Vaccines

When I lived in Ann Arbor, my children attended a public school where upwards of 15% of kids were not vaccinated for mumps because their left-wing parents didn’t trust the vaccine industry. Meanwhile on the right end of the political spectrum, Tea Party heart throb Michelle Bachman famously accused vaccines of causing autism. How is it that such an advanced technologic country harbors so many vaccine luddites?

A quick glance at the U.S. small pox epidemic of 1900 offers a clue.

At the turn of the 20th century, the United States had managed to avoid a major smallpox epidemic for the better part of a generation. Then a small wave of illness washed over communities of black farmers and laborers in a few southeastern states. The white community wasn’t alarmed however, believing the disease, which some called “nigger itch,” would stay contained to that population, who they were convinced had brought it upon themselves through one or another vice. As one local newspaper put it at the time: “Up to the present, no white people have been attacked and there is positively no occasion for alarm.”

Then of course the disease began spreading to white people. The smallpox virus, it turns out, was colorblind. Yet although white people did become alarmed at this point, they didn’t turn out in droves to get vaccines. Instead, a vocal minority argued vehemently that the vaccine was of no benefit.

It should have been obvious to even casual observers that the smallpox vaccine was a lifesaver. During the Franco-Prussian War of 1870-1871, you see, a smallpox epidemic had swept through Europe killing millions of citizens. The French army, which had half-heartedly vaccinated some of its troops, fared better than the population, but still saw over 23,000 troops fall victim to this terrible scourge. Meanwhile on the other side of the battle lines, the Prussian army, almost all of whom had been vaccinated, remained strong. Out of over 800,000 troops, only 457 died from smallpox.

Good policies often depend on good evidence. In healthcare, our gold standard for good evidence is the randomized controlled trial, in which, for example, half the patients receive a new drug and half receive a placebo. When the drug and placebo patients are determined at random, we can be pretty confident that any subsequent differences between the groups—like a higher mortality rate in the placebo group—occur because one group got the drug and the other didn’t.

But sometimes, non-experimental evidence is so striking that conducting a randomized trial—withholding the new intervention from half of an experimental population—feels immoral. That’s one reason there has never been a randomized trial of the smallpox vaccine. Indeed, it is why many early medical advances became standard of care without anyone seeing the need for a placebo controlled experiment.

Yet a mere thirty years after the end of the Franco-Prussian War, when the smallpox epidemic swept through the United States, a whole host of intelligent people refused to be vaccinated, convinced that the vaccine did more harm than good.

How could they hold this belief? For starters, the United States had much stronger libertarian leanings than places like France and Germany. But another fascinating phenomenon also contributed to people’s anti-vaccine views: people didn’t believe the evidence. They remained unconvinced because of what us in the medical research world would call concern about “confounding.”

A confound occurs in research when two groups differ not only in the intervention of interest, but also in some other possibly unmeasured way. This makes it hard to tell whether the difference between the groups is caused by the intervention in question–the vaccine in this case–or from this other factor.

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This vigorous on line debate confirms my main point. Many people on the right and the left will not be convinced of vaccine safety without randomized trials, trials which most medical experts would see as being immoral by allowing people, unsuspecting children, to go without important preventive measures. The same was true for many folks during the small pox epidemic, until the scope of the outbreak was so great that fear of the vaccine got trumped by fear of the disease. I hope the same doesn’t happen with most of our well proven childhood vaccines, all of which I have received as have my children. Oh yes, and I am old enough to have been vaccinated for small pox.

On another note. Thanks for reminding me that Bachman made a claim about mental retardation not autism.

And finally, let’s all remain open minded and respectful. These are complicated issues. I do not believe that routine vaccines cause autism. Nor do most medical experts. But it was the Lancet which published the article that got this debate where it is today. And although that journal has retracted that article, who can blame concerned and loving parents for wondering whether the medical community is hiding something from them.

Very educational article, indeed. Regarding the fact that the drug corporations are making new generation vaccines, which are called “bioterrorism” vaccines and for example, it is the disreputably reactive smallpox vaccine, that it has never tested for safety in clinical trials. And not only the drug corporations demand that the Congress provide them a total officially authorized protection for all the vaccine-induced injuries and deaths, they are furthermore demand that the specific bioterrorism vaccines are excepted from standard federal protection and efficiency standards. I suppose that they have no right to play with our health.

Could you please show me any true study on any vaccine? So far, all I can find is a vaccine and instead of a true control group it is tested against a single ingredient from the vaccine or another vaccine. Where are the controls? Thanks!